New research indicates that individuals who use psychedelic substances like LSD and psilocybin may experience a significant increase in unusual visual phenomena, such as seeing patterns or intense colors that are not there. The study, published in the Journal of Psychopharmacology, sheds light on the potential side effects of psychedelics outside of clinical settings.
The exploration into psychedelics has entered a renaissance, with mounting evidence supporting their potential therapeutic benefits for a variety of psychiatric disorders, from depression to alcoholism. However, the use of these substances in uncontrolled, everyday environments raises questions about their safety, especially concerning the risk of enduring visual disturbances known as hallucinogen persisting perception disorder (HPPD).
Despite the clinical promise of psychedelics, a comprehensive understanding of their risks, particularly regarding visual anomalies that may occur long after the drug’s effects have worn off, has remained elusive. The research team set out to explore the prevalence and intensity of these visual experiences among the general populace, aiming to provide a clearer picture of the risks involved with the naturalistic use of psychedelics.
“Whereas findings from case reports and cross-sectional studies suggest that naturalistic psychedelic use may be associated with unusual visual experiences that occur after the acute pharmacological effects have subsided, such findings need to be replicated in longitudinal studies to better understand potential cause-and-effect relationships,” explained study author Otto Simonsson, a postdoctoral researcher at Karolinska Institute’s Department of Clinical Neuroscience.
The researchers recruited a vast cohort of 9,732 participants from the United States and the United Kingdom. These participants were carefully selected to mirror the demographic makeup of their respective countries in terms of sex, age, and ethnicity, thus ensuring a broad representation.
Conducted over a two-month period, the study collected baseline data on the participants’ psychedelic use and their experiences of unusual visual phenomena. This data collection was repeated two months later, providing a longitudinal glimpse into the relationship between psychedelic use and visual experiences.
Participants were asked to report any psychedelic drug use within the study period and to describe any unusual visual experiences, such as seeing halos around objects or witnessing colors becoming more intense. Additionally, the study inquired about encounters with unidentified aerial phenomena.
One of the most notable findings was the correlation between first-time psychedelic use and an increase in unusual visual experiences. Participants who had never before used psychedelics but did so during the study period reported a greater increase in these experiences than individuals who had used psychedelics previously. This suggests that naivety to psychedelics may predispose individuals to more pronounced visual disturbances, highlighting a potential area of concern for first-time users.
The study also examined the prevalence of specific types of visual disturbances among users. For instance, the brightness or intensity of colors was reported to increase more frequently among psychedelic users, as were the occurrences of seeing with open eyes patterns or objects that were not actually present. Additionally, users reported a higher sensitivity to oscillations or flashing light sources, indicating a broad spectrum of visual sensitivity alterations following psychedelic use.
Interestingly, the study found a moderate correlation between the reporting of unusual visual experiences and sightings of unidentified aerial phenomena (UAP). This aspect of the research underscores the broad range of visual anomalies that individuals may experience following the use of psychedelics, extending beyond mere hallucinations to include more complex visual distortions.
These findings collectively suggest that the use of psychedelics can indeed lead to a variety of unusual visual experiences. “The findings in this study suggest that psychedelic use may elicit unusual visual experiences that occur after the acute pharmacological effects have subsided, especially among those who have not used psychedelics previously,” Simonsson told PsyPost.
But as with any study, the new research includes some limitations. The observational nature of the research means that while a link can be established between psychedelic use and visual anomalies, causation cannot be definitively proven. The reliance on self-reported data also introduces the potential for recall bias, where participants might not accurately remember or report their experiences.
“The current results suggest that public health campaigns communicate to those who intend on using psychedelics (e.g., in states that have liberalized laws around psilocybin and other psychedelic substances) that unusual visual experiences are possible consequences of use,” the researchers wrote. “While such experiences may not necessarily be associated with impairment or distress, clinicians should be prepared for reports of unusual visual experiences among patients who report recent psychedelic use and monitor these symptoms over time so as to determine the best course of action. Future longitudinal research should investigate the time course of these unusual visual experiences and if, for whom, and under what circumstances they might represent a significant adverse outcome requiring intervention.”
The study, “Longitudinal associations between psychedelic use and unusual visual experiences in the United States and the United Kingdom“, was authored by Otto Simonsson, Peter S Hendricks, Cecilia UD Stenfors, Simon B Goldberg, Ludwig Honk, and Walter Osika.